The field of the present invention is architectural fixtures and mountings for lighting.
Typical yoke mounted fixtures utilize external opposed parallel surfaces on a fixture housing. These surfaces are either smooth or include radial serrations. The yoke associated therewith has matching inner surfaces alignable with the fixture housing surfaces. Concentrically arranged fasteners compress the surfaces together to create a friction joint that will prevent the yoke from slipping and losing the fixture aim. Smooth surfaces can be unreliable and allow slippage. This can be of concern, particularly for architectural lighting fixtures which may be difficult to access once in place. With serrated surfaces, slipping is unlikely. However, adjustability is limited by the pitch of the serrations.
Concentrically arranged fasteners acting as trunnions are also problematic with larger fixtures. If studs are employed in the housing, the yoke must be bent for assembly or disassembly. Bolts through the yoke can make assembly difficult and provide inadequate pivot members.
Architectural light fixtures have experienced additional issues. The housings typically have cavities which heat and cool with cycling of the light. Air pressure can vary significantly within the housings under such cycling. This can ultimately result in seal damage, leakage and lens distortion or failure.
An additional issue with exterior light housings is the employment of photocells to control the light. For lower wattage fixtures with large housings, internal temperatures do not greatly vary. In such fixtures, button-type photocells are typically employed. These photocells have temperature limitations and are impractical for higher wattage lights. For fixtures where the temperature will vary substantially, external photocell devices are typically employed. These photocells know as “twist lock” type photocells require that they remain in a vertical position to prevent water intrusion and subsequent failures. The external positioning of the cells also detracts from the architectural aesthetics.